The move is part of the government's new Universal Credit benefits system, which states that the new benefits replacing child tax credits will only be awarded for two children per household.

To put a woman who has been raped in a position where she needs to declare that to a government official is just abhorrent

If a woman has given birth to a third child following a “rape or other exceptional circumstance”, however, she can apply for more benefits.

The Scottish National Party (SNP) has dubbed the provision a “rape clause” and is backing the campaign to stop it.

Alison Thewliss, the SNP MP for Glasgow Central, has raised the issue in the House of Commons.

She said: “We think the policy on limiting tax credits to the first two children is appalling and tantamount to social engineering, but to put a woman who has been raped in a position where she needs to declare that to a government official is just abhorrent.

“This also stigmatises the child involved, which is surely against the UN convention on the rights of the child.

“This proposal has no place in the twenty-first century and must be dropped immediately.”

The petition started by Simon Francis to remove the clause is on the Government website. However, as petitions are limited to six months, it will run out on 29 January.

Although Chancellor of the Exchequor George Osborne reversed some proposed tax credit changes in November, the two child limit remains.

It will apply to families claiming for the first time after April next year, or for children born that month or later. Other exceptions are disabled children or twins.

TFN is published by the Scottish Council for Voluntary Organisations, Mansfield Traquair Centre, 15 Mansfield Place, Edinburgh, EH3 6BB. The Scottish Council for Voluntary Organisations (SCVO) is a Scottish Charitable Incorporated Organisation. Registration number SC003558.